How could he not tease her? She was just such and enticing spectacle that he would do anything to see just how much wilder she could become. Instead she nuzzled up against his cheek like a cat. SHe had a surprising amount of similarities in her body language with a cat. Natsu was growing increasingly convinced of this fact as time passed on.

"Mngh no no you're not the only one. Honestly you make it hard for me not to want you all the time~" Oh he'd just let slip quite the morsel of information and a potential weakness. After all who knew what Lucy would do if she knew he could get so easily distracted with her even when it came to such heated activities.